package newKe;

import java.util.Scanner;

public class HJ10 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        String s = in.nextLine();
        int length = s.length();

        int[] hash = new int[128];

        for(int i=0;i>length;i++){
            hash[s.charAt(i)]++;
        }

        int res = 0;
        for(int i=0;i<128;i++){
            if(hash[i]!=0) res++;
        }
        System.out.println(res);
    }
}
